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If that is not enough decrease in air flow and assuming for now the charge is proper, would changing the filter to a MERV 13 from a MERV 8 help? My reading through the forums seems to indicate you folks favor the MERV 8. (Unfortunately this system only has provision for 1" filters 16x20)

If that is not enough decrease in air flow and assuming for now the charge is proper, would changing the filter to a MERV 13 from a MERV 8 help? My reading through the forums seems to indicate you folks favor the MERV 8. (Unfortunately this system only has provision for 1" filters 16x20)

If that is not enough decrease in air flow and assuming for now the charge is proper, would changing the filter to a MERV 13 from a MERV 8 help? My reading through the forums seems to indicate you folks favor the MERV 8. (Unfortunately this system only has provision for 1" filters 16x20)

Well, if U were using a cheap fiberglass throwaway filter the velocity would be around 665-FPM; when initial velocity, according to manual D, through a clean throwaway filter ought to be 300-FPM.

With the higher pressure-drop filter; not best option; the drop went to 17F.
If U get the air flow right; low enough; it should begin to dehumidify.

OK it's been a few hours having changed -15% CFM from 1020CFM orig setting and a MERV 13 in place.
Return temp is 72 as is the room temp, Indoor Humidity reads 63% (First floor is 74 and humidity is 52%) Outdoor temp is 92

Raise the thermostat up 1F and set the fan to "ON" for 30 minutes. Humidity should only go up 2-3%RH... and temperature maybe 1F... unless it's pulling in a lot of attic air. IF when running the fan only you can "smell the attic", then that may answer your question.

Raise the thermostat up 1F and set the fan to "ON" for 30 minutes. Humidity should only go up 2-3%RH... and temperature maybe 1F... unless it's pulling in a lot of attic air. IF when running the fan only you can "smell the attic", then that may answer your question.

Consider that there is 1 lb. of moisture per ton of coil retained on the coil at the end of the cooling cycle. The moisture on the coil will evaporate back to the home is 30-45 mins. with the fan "on". 2-3 lbs. of moisture into 1,800 sqft. of space will raise the indoor %RH 8-10%.
Regards TB

Consider that there is 1 lb. of moisture per ton of coil retained on the coil at the end of the cooling cycle. The moisture on the coil will evaporate back to the home is 30-45 mins. with the fan "on". 2-3 lbs. of moisture into 1,800 sqft. of space will raise the indoor %RH 8-10%.
Regards TB

At the moment you have a 4 degree split, and that is a major issue! It's time to call a tech out to your home. Regardless of what you think is going on. The system must work correctly before you can fix the other issues.